Self-Sealing Closure System and Method

ABSTRACT

The self-sealing closure system includes a flexible, overlapping, interlocking closure with a continuous backing membrane to provide a secure, durable, and redundantly impermeable barrier operated by finger pressure or by an optional easy-to-operate, zipper-like cursor, with an optional locking end cap.

This invention claims the priority of Provisional Patent Application dated Feb. 11, 2020 by Leonard A Duffy of Hinesburg Vermont entitled “Self-Sealing Closure”

BACKGROUND

There is a need for an innovative self-sealing closure system which is secure, durable, and easy to operate; in particular a closure system which is flexible, non-grabbing, readily cleanable, reusable, and impermeable. Such a system may be used for any application requiring a secure, easy-to-operate impermeable edge closure including but not limited to: PPE Protective Equipment Ensembles as used in chemical, biological, and radiological CBR incidents; spacesuits and vehicle air locks; underwater apparel and equipment; flexible containers; hyperbaric chambers; and diverse consumer and industrial applications including packaging, apparel, footwear, raingear, sports equipment, luggage; and for other general closure and fastening applications which may or may not require a sealed connection.

Prior Art includes a variety of pressure sealing zippers, zip-lock type closures, multitrack systems, as well as thermal and chemical seals. For example: Krupp, U.S. Pat. No. 2,385,816, describes a zipper surrounded with overlapping rubber flaps. Brown, U.S. Pat. Nos. 3,982,016 and 4,308,644, discloses interdigitating edge connectors combined with an elastic pressure strip operated by a slide mechanism. More recently, Yadav et al, U.S. Pat. No. 9,248,322, presents a protective suit with zipper closure protected by an overlapping flap. McLachlan, U.S. Pat. No. 9,675,144 discloses a pair of overlapping flaps providing a double barrier over a choice of zipper, Velcro or magnetic closure. In general, these types of solutions provide secondary means for sealing an edge connection which is primarily connected with a non-sealing attachment mechanism, thereby providing redundancy but not necessarily integrity of the whole.

A variety of multi-track zip fasteners such as those used for reclosable plastic bags as disclosed by Herrington, U.S. Pat. No. 4,532,652, and Nanba et al, U.S. Pat. No. 9,550,617, and others, may also provide self-sealing edge closures. Many of these systems provide adequate security but may be compromised by lack of integrity due to excess flexure, difficulty of use, or limited durability (use cycles), or functional inadequacy at larger scales.

Systems depending on chemical or thermal sealing are generally only useful for a single use and are therefore not considered relevant to the current need.

Closure systems including pluralities of interdigitating protrusions, such as Tuma, U.S. Pat. No. 8,839,495, Morar, U.S. Pat. No. 10,292,462, Dyllong, U.S. Pat. No. 9,775,411, and Bronson, U.S. Pat. No. 10,342,300, each have certain advantages, though do not appear to provide the simplicity and potential sealing redundancy of the present invention.

A number of fastening systems have been proposed which incorporate pluralities of interlocking protrusions such as Kaneko, U.S. Pat. No. 5,212,853, Adams et al, U.S. Pat. No. 9,198,483, and Tempesta, U.S. Pat. No. 9,565,903. Generally, the protrusions are on some form of stem, thus allowing flow between and below the coupling. While unique as fastening mechanisms, these systems do not appear to provide an effectively sealing connection.

The present inventor, in Duffy, U.S. Pat. No. 7,950,114, teaches a device including dome-like protrusions integral with a grid structure which provides a relatively high degree of gaseous or liquid security when static, but might potentially leak during excessive flexure. Illustrated as Prior Art.

Therefore, there remains a need for an easy to use, durable, effective self-sealing flexible closure.

DRAWINGS

The attached drawings are intended to schematically illustrate the basic elements of the closure system.

FIG. 1: Perspective view of the self-sealing closure partially engaged

FIG. 2A: Plan view of a portion of the closure

FIG. 2B: Longitudinal section of a first portion

FIG. 2C: Longitudinal section of the engaged portions

FIG. 2D: Longitudinal section of a second portion

FIG. 2E: Lateral section of first portion

FIG. 2F: Lateral section of engaged portions

FIG. 2G: Lateral section of second portion with attached substrate

FIG. 3A: Plan view of quadrille pattern

FIG. 3B: Plan view of diagonal pattern

FIG. 4A: Longitudinal section of sliding cursor

FIG. 4B: Cross section of cursor at divider strip

FIG. 4C: Side view of cursor

FIG. 4D: End view of cursor, mouth end

FIG. 5: Longitudinal section End Cap

FIG. 6A-D: Schematic Examples of Potential Applications

SUMMARY OF THE INVENTION

The Self-Sealing Closure System includes two generally hermaphroditic overlapping portions, at least segments of which are resiliently flexible, with each portion including a grid-like base structure with a contiguous bottom membrane enclosing a plurality of receptor chambers, and a plurality of corresponding dome-like protrusions which may be pressed into respective corresponding receptors to bond and seal the portions together with optional reopening and reuse. A key feature of this mechanism is that the generally flat bottom surfaces of dome-like protrusions are effectively flush with the top surface of the ribs of the grid as well as with the bottom surfaces of corresponding protrusions along a common joining plane, thereby providing an effectively self-sealing continuous joining plane while the contiguous bottom membrane provides a secondary redundant level of closure.

As an edge closure, the nodules and receptors may be arrayed in either a diagonal or quadrille pattern, and may include one or more longitudinal rows of those elements, with multiple rows providing greater strength and redundancy. A continuous longitudinal rail provides a redundant sealing barrier as well as a guide for a cursor as described below.

The system also includes an integral lateral selvage strip for attaching to a substrate by welding or other means. The selvage strip is preferably configured so that its upper surface is coplanar with the joining plane, thereby minimizing offset stresses when subjected to lateral sheer.

The portions are engaged by application of a generally compressive force to the generally aligned components, which force may be affected by application of compression such as finger/thumb pressure, or preferably by the disclosed longitudinally sliding cursor.

The cursor includes a structure with a separating bar and a compressive slot, so that when moved in a first longitudinal direction the portions are drawn together and interlocked and when moved in an opposite direction the portions are sequentially separated. The cursor also includes a pull-tab with a locking mechanism which may be latched to either another cursor in opposed direction or to an end cap.

An optional self-sealing end cap with a latching edge for receiving the locking mechanism is also included to provide a completely sealed connection.

The present invention significantly improves upon prior art, Duffy U.S. Pat. No. 7,950,114 by including a continuous membrane along the bottom of the grid-like structure and also providing a rail, an optional sliding cursor, and a latching end cap for fully and redundantly sealing the entirety of a lineal edge; thereby providing an easily operated overlapping connection with multiple redundant sealing surfaces which is strong, highly flexible and durable.

Prototypes of the Duffy prior art system, made in diverse materials and sizes, have proven to be strong, highly flexible, and easy to operate by either finger pressure or by zipper-like cursor/sliders, generally surpassing hook-and-loop closures in most critical aspects. The system differs significantly from other zipper-type solutions in that the portions are overlapped in lieu of a segmented linear edge connector; this aspect provides a fastening mechanism comprised of multiple redundant individual cells, effectively flush with the base body's (i.e. garment's) surface. Therefore, the system affords significant strength with a relatively soft and flexible rubber-like material, which may be selected from a variety of options for the task at hand.

The Self-Sealing Closure System includes a number of significant improvements over other extant systems: In comparison to a pressure sealing zipper, this solution provides an overlapping sealing area with multiple redundant independent self-sealing cells. Therefore, it is considerably more robust and durable, and less susceptible to jamming or breakage. Because it is effectively flush with the garment surface, it is less susceptible to inadvertent mechanical damage. In comparison to a “Ziploc”-type closure, this system includes multiple barrier cells which are self-engaging and not subject to misalignment or tearing. In comparison to a thermally sealed coffer dam, this system is fully reusable multiple times and may be operated solely by the wearer. In comparison to multitrack closures, this system provides similar redundant sealing capacity in an easy-to-use format which is effectively flush with the garment surface.

Some inherent advantages of the invention include: Overlapping portions provide significantly greater shear strength with less stress on the engaged seal than other edge joining mechanisms. The system is highly flexible, composed of rubber-like portions which when engaged act generally as a single flexible structure. The device is extremely light weight due to its open grid structure, compact profile, and low-density materials. The portions may be readily integrated with a synthetic fabric substrate by rf or heat welding or common adhesives. Alternatively, the system may be over-molded onto fabric. The inherent flexibility of the device allows it to be compactly folded for stowage and it may be readily applied to curved openings. The device allows easy, intuitive and fast operation similar to a conventional zipper. The inherent simplicity of the device and its manufacturing process assure relatively low cost, reliability and durability.

The proposed solution utilizes relatively simple common manufacturing systems, 3D printing, rotary die molding, or injection molding, and known materials including thermoplastic elastomers, LSR Silicone and/or rubbers, which allow for economical and efficient manufacturing. Closure systems may be attached to extant CBR materials via welding, adhesive, or other commonly used practices. No significant cost differential versus currently used closure systems is foreseen other than initial development cost.

The proposed solution is intuitive and easy to operate, similar to common zipper systems, though overlapping. The gridded structure may be arrayed in a quadrille or a diagonal pattern, each arrangement having unique advantages for distinct types of application. and portions may include a single longitudinal row of complementary nodules and receptors or multiple rows for higher strength and greater redundancy, as well as for potential lateral adjustability.

The invention may be applied to a wide range of edge fastener applications including: an, zipper replacement, hook and loop (i.e. Velcro®), snaps, laces, or other edge connections especially where water resistance is desirable; as a sealing closure for specialty apparel such as CBI or medical protective equipment; for fire safety equipment, flight-suits, etc., when made of silicone (LSR); as an air lock for medical or outer space applications; as a self-sealing closure for containment structures ranging from plastic food or waste bags to pouches, boxes, equipment covers, truck tarps, etc. (I suggest you rework this section as separate lists.) Generally, such edge closure applications require inclusion of a lateral selvage strip for attachment to a substrate material; however, the present closure system may also be used, without such a lateral selvage, as a linear connection, such as for a strap, band, wrap, or belt, wherein the portions are adjustably overlapped longitudinally to provide an effectively blind connection.

DESCRIPTION OF THE INVENTION

As used herein, the terms “top” and “bottom” are intended as relative only in respect to describing the configuration of parts of the invention and have no relationship to gravitational position. Likewise, the term “plane”, as in “common joining plane” is intended to describe only the relative juxtaposition of parts in a static state, in lieu of a continuing geometric abstraction, thus the effective joining plane of the generally elastic and flexible structures may bend or twist relative to common orthogonal orientation. The term “elastomeric” is intended to include a selection or rubber-like materials which are both flexible and resilient with sufficient shape memory to function as designed. The term “containment device” is intended to include a wide range of bags, boxes, luggage, and similar devices.

As schematically illustrated in FIGS. 1 and 2 the Self-Sealing Closure System includes a first portion 01 for interconnecting with a second portion 02, the portions being effectively hermaphroditic. Each portion includes a plurality of geometrically arranged nodules 03, each such nodule having a generally bulbous upper surface 04 and a generally planar underside 05 which is coincident with a common joining plane 14.

Segments of the underside 05 overhang receptors 06, whilst other segments are coincident with rib tops 09 at the interstices of ribs 07. The ribs 07 are in general arrayed as a grid-like structure; each such rib 07 having a rib top 09, sidewalls 10, and rib bottom 11, wherein the rib top 09 is also coincident with the common joining plane 14 and the undersides 05.

Receptors 06 are defined by the undersides 05 of surrounding nodules 03, a plurality of rib sidewalls 10, and a contiguous basal membrane 12; the basal membrane being integral with the rib bottoms 11.

Each receptor 06 is associated with a receptor opening 13, defined by the bulbous upper surfaces 04 of surrounding nodules 03.

The portions are configured so that the depth Z1 of each receptor, measured from the common joining plane 14 to the membrane 12 is at least as deep as the height Z2 of each nodule 03 from the joining plane 14; the width X1 of the space between ribs is at least as large as the width X2 of each Nodule 03; and the distance Y1 between adjacent nodules 03 is at least as great as the width Y2 of each rib top.

Therefore, when at least segments of at least one portion 01,02 are resiliently elastic the corresponding respective nodules 03,03′ of each portion may be squeezed through corresponding receptor openings 13,13′ by application of a relative compressive force C, and resiliently expand into a corresponding respective receptor 06,06′, so that the first portion 01 is interlocked with the second portion 02, with each nodule 03 entrapped within a corresponding receptor 06; the undersides 05 of each corresponding nodule and corresponding rib tops 09 are congruent with the common joining plane 14, so that the nodules of each portion retain each other, thereby providing a generally impermeable seal between the portions 01,02 and generally resisting release except by sequentially pulling nodules 03 from their respective receptors 06. The basal membrane 12 provides redundant enclosure of the portions so as to further resist inadvertent leakage in the event of concentrated stress at the joining plane 14.

The nodules 03 and associated receptors 06 may be arrayed in either a quadrille or diagonal pattern relative to the longitudinal axis as illustrated in FIGS. 3 A-B. As an edge closure, a single longitudinal row of half-nodules and receptors arrayed in a diagonal pattern, represents the effective minimum closure width, although preferred embodiments for critical sealing applications, would generally include at least one row of full nodules 03, as in FIG. 3B, for greater strength and redundancy.

A preferred embodiment also includes a continuous longitudinal rail 15 to affect a redundant sealing edge as well as to affect an alignment guide for engaging the portions.

Portions 01,02 of a preferred embodiment also each include a lateral selvage strip 16 for attaching the portion to a substrate 17. The selvage strip is preferably configured so that its upper surface is coincident with the joining plane 14, thereby minimizing torquing of the enjoined assembly due to lateral or torsional sheer forces.

In a preferred embodiment, receptors 06 have a somewhat greater volume than the volume of nodules 03, resulting in void spaces 18, so as to allow the nodules to resiliently expand into their original shape within the confines of corresponding receptors. A volumetric differential of approximately 10-15% is preferred. At least segments of at least one of the portions 01,02 is made of a flexible resilient material such as rubber, thermoplastic urethane (TPU), silicone rubber, or other flexible resilient material, so that the nodules 03 may be deformably inserted through the relatively narrow receptor openings 13 and resiliently expand into their respective receptors 06.

Although the portions 01,02 may be engaged by application of a general compressive force, such as pressure applied between thumb and forefinger to generally aligned unconnected portions, a preferred embodiment also includes a longitudinally sliding cursor 20.

As schematically illustrated in FIGS. 4 A-D, the cursor 20 includes: a structure with an entrance chamber 21 with longitudinal aligning walls 22, and a separator bar 23 separating distinct entrance slots for each portion 01,02, above and below such bar. The cursor also includes: a longitudinally tapered chamber 24 for pressing nodules 03,03′ into corresponding respective receptor openings 13,13′, the chamber 24 terminating at a compressive slot 25; a generally expanding exit chamber 26 terminating at a chamfered or rounded mouth 27; slotted edges 28 to allow passage of the selvage strips 16,16′ associated with each portion; and means for applying longitudinal opening and closing forces A,B via a pull tab 30 or thumb tab 33.

The cursor 20 is configured so that each portion 01,02 can easily slide through entrance chamber 21, tapered chamber 24, exit chamber 26, and slotted edges 28, confined and laterally directed via aligning walls 22. Compressive slot 25 is configured to confine and sequentially squeeze respective resilient nodules 03 fully into their corresponding receptors 06.

As the cursor 20 is directed in a first longitudinal direction A, the nodules 03 of each portion 01,02 are sequentially pressed through respective receptor openings 13, then fully squeezed into their corresponding receptors 06 so that the nodules 03 may resiliently expand, resulting in respective corresponding undersides 05 and rib tops 09 securely interfaced along the common joining plane 14. As the cursor 20 is directed in an opposite longitudinal direction B, the portions 01,02 are sequentially separated by the separator bar 23 and exit separately through their respective slots at the entrance chamber 21.

As illustrated here in FIGS. 4 A-D, the cursor 20 is preferably made as a single molded part of a relatively strong stiff thermoplastic or metal capable of providing sufficient structural integrity to retain the “S” shaped cross section and provide consistent compressive strength at the compressive slot 25.

In the preferred embodiment illustrated in FIG. 4, pull tab 30 is connected by a hinge to the cursor 20 to provide means for applying lateral force to the device, and to fold flat against the cursor structure when not being used. The pull tab is here illustrated as being connected via a “living hinge” 31 as may be utilized with certain thermoplastics. However, the pull tab 30 may also be connected via any type of a hinging pin and slot mechanism as are commonly known in the field of zippers.

The pull tab 30 preferably includes a locking mechanism 32, which is an integral latch projecting slightly less than perpendicular from pull tab 30 at or near its terminus. The locking mechanism 32 is configured so as to effect a tight and secure connection with either a second cursor 20′ in opposite orientation or with an end cap 40.

For many applications, such as in protective apparel, it may be convenient to include a combination as illustrated or sets of pull tabs on opposite faces.

A simple perpendicularly projecting thumb tab 33 may be integrally molded as part of the cursor 20, as also shown for illustrative convenience in FIG. 4 projecting from the opposite face of the cursor from the pull tab 30. For many applications such as in protective apparel it may be convenient to include a combination as illustrated or sets of pull tabs 30 on opposite faces of the cursor.

As schematically illustrated in FIG. 5, an end cap 40 is included in the preferred closure system to seal together two portions 01, 02 at a closed-end terminus. The end cap 40 includes a single opening chamber 41 corresponding with entry chamber 21 of a cursor 20, the opening chamber 41 tapering to a pinching segment 42 and having faces 43 configured to interface precisely into the cursor entry chamber 21. The end cap also includes a latching edge 44 for tightly receiving and latching with locking mechanism 32 of pull tab 30. Therefore, when terminal selvage segments 16,16′ of a longitudinal set of portions 01, 02 are fully sealed together within end cap 40, and the cursor 20 is pulled tightly to the end cap 40 and latched in place with locking mechanism 32, the portions become impermeably interlocked to provide a fully sealed system.

As examples of potential applications, FIGS. 6A-D schematically illustrate several generic articles incorporating the present invention in diverse configurations:

FIG. 6A schematically illustrates a fully sealed protective garment with integral headpiece in which a closed ended embodiment of the present closure equipped with cursor 20 and end cap 40 extends generally diagonally from a shoulder to opposite hip.

FIG. 6B schematically illustrates a front opening jacket, such as outerwear for winter sports, having complementary portions of the closure 01,02 on each edge, equipped with a cursor 20, for providing a weather resistant sealed front which can also be manually pinched together at any point 50 to allow partial closure and ventilation. Fully opening embodiments of this type require a simple mechanical stop 51 at each end of the portion on which the cursor 20 resides.

FIG. 6C schematically illustrates a waterproof boot with an open-ended embodiment of the closure equipped with cursor 20′.

FIG. 6D illustrates a weatherproof equipment bag with a closed end embodiment of the closure equipped with two cursors 20,20′ in opposite orientations connected via locking mechanism 32.

Therefore, a method of interlocking two bodies in a sealed juxtaposition includes the following steps: First, providing first and second portions of the device as described above; secondly, integrally attaching the portions to the respective bodies; thirdly, generally aligning nodules of the first portion with receptor openings of the second portion; and fourth, sequentially compressing the portions together until the nodules of each portion are fully engages within their respective corresponding receptors.

As can be seen from the above examples, the self-sealing closure system has a wide variety of potential functions which may or may not include all of the elements described above to fulfill any one such function. The elements may be manufactured in a range of elastomeric materials and at virtually any scale within the capacity of known manufacturing methods (3D printing, injection molding, continuous rotary die molding, etc.). 

Therefore, having thus described the invention in detail, I hereby claim the following:
 1. A self-sealing closure including a first portion for interlocking with a second portion, said second portion comprising: A plurality of nodules, each said nodule having a generally bulbous upper surface and a generally planar underside which partially overhangs a receptor between the ribs of a grid-like structure, each such rib having a rib top, sidewalls and a rib bottom; and said nodule protruding from an interstice of said ribs wherein said underside is generally coplanar with said rib tops on a common joining plain; and wherein each said receptor is defined by a plurality of said undersides, a plurality of said sidewalls, and a contiguous membrane integral with and generally coplanar with said rib bottoms, each said receptor having a volume somewhat greater than the volume of each said nodule; and wherein said second portion is configured so that the width of the space between adjacent said ribs is at least as wide as the width of each said nodule and the depth of said ribs as measured from said rib top to said rib bottom is at least as deep as the height of said nodules above said ribs, and the distance between adjacent said nodules is at least as wide as the width of said ribs; and further wherein at least parts of said second portion also includes elastomeric segments and a lateral selvage strip; so that, when said nodules of said second portion are generally aligned with receptor openings of said first portion, and said first and second portions are subjected to a generally compressive force, said elastomeric segments generally deform to allow corresponding respective nodules of each said portion to bypass until said undersides of corresponding said nodules expand into an interfaced disposition with corresponding undersides, and corresponding said rib tops interface along said common joining plane; Thereby forming an interlocked assembly connecting said first and second portions which is also highly resistant to the flow of liquid, gaseous, or biological matter, and which said assembly may be disconnected by sequentially peeling said portions apart.
 2. A closure as in claim 1, wherein said generally compressive force is provided by longitudinally sliding cursor; said cursor comprising a generally tapered entrance chamber with means for alignment and a separator bar, a generally tapered chamber terminating at a compressive slot, and a generally expanding exit chamber terminating at a mouth; wherein said cursor comprises a singular integral structure with longitudinal alignment walls and longitudinal slots for said selvage, configured so that when said sliding cursor is directed in a first longitudinal direction said first and second portions are sequentially into an interlocked assembly; and when said cursor is directed in a second opposite longitudinal direction said first and second portions a sequentially separated.
 3. A closure as in claim 1 comprised of a generally elastomeric material.
 4. A closure as in claim 1, wherein said first and second portions each include an integral lateral selvage strip for attachment to a substrate.
 5. A closure as in claim 1, wherein said first and second portions each include an integral lateral selvage strip for attachment to a substrate.
 6. A closure as in claim 1, wherein said first and second portions are segments of protective apparel.
 7. A closure as in claim 1, wherein said first and second portions are segments of an air lock.
 8. A closure as in claim 1, wherein said first and second portions are joining segments of a containment device.
 9. An interlocking closure for providing a generally impermeable seal between a first body and a second body comprising: A first portion integral with said first body including a plurality of receptors and associated receptor openings within a grid-like structure, a plurality of generally bulbous nodules protruding above a common joining plane, and a contiguous membrane integral with bottom surface of said grid-like structure and with said first body; A second portion integral with said second body; Said first and second portions configured so that, when subjected to a generally compressive force, said nodules of said first portion enters through said receptor openings and resiliently expands within said receptors of said second portion, thereby providing a sealed connection along said common joining plane between said first and second bodies.
 10. An interlocking closure as in claim 9, where said first and second bodies are segments of protective apparel.
 11. An interlocking closure as in claim 9, wherein said first and second bodies are segments of an air lock barrier.
 12. An interlocking closure as in claim 9, wherein said first and second bodies are segments of a device.
 13. An interlocking closure as in claim 9, wherein said first and second portions are composed of a generally elastomeric material.
 14. An interlocking closure as in claim 9, wherein said generally compressive force is provided by a longitudinally sliding cursor, and said cursor comprising a generally rigid structure with a generally tapered chamber for squeezing the first and second portions into an engaged juxtaposition when said cursor is moved in a first longitudinal direction, and a separating bar for alternatively disengaging assembled said portions when said cursor is moved in a second longitudinal direction.
 15. An interlocking closure as in claim 9, including a longitudinal rail for guiding a cursor and sealing the edges of said assembly.
 16. An interlocking closure as in claim 2, including said sliding cursor and a self-sealing end cap, said end cap including means for sealing together end selvage segments and said membranes of each said portion and tightly connecting with said cursor, and also including a pull-tab latching mechanism for locking said cursor to said end clamp, configured so that the portions are impenetrably squeezed together as said cursor and said end clap engage.
 17. An interlocking closure as in claim 9, with said membrane extending laterally as a selvage strip.
 18. An interlocking closure as in claim 2, wherein said cursor includes an integral pull tab with optional latching means, which may be used to securely connect with the choice of a second said cursor in opposite disposition or with an end cap.
 19. An interlocking closure as in claim 9, wherein said cursor includes an integral pull tab with latching means, which may be used to securely connect with the choice of a second said cursor in opposite disposition or with an end cap.
 20. A method of interlocking two bodies which is highly resistant to the flow of liquid, gaseous, or biological matter, comprising the following steps: a. Providing first and second portions as per claim 1; b. Integrally attaching said first portion to a first body; c. Integrally attaching said second portion to a second body; d. Generally aligning said nodules of said first portion with said receptor openings of said second portion; e. sequentially compressing said first portion toward said second portion, until corresponding said nodules resiliently expand into said receptors and undersides of corresponding respective nodules and said rib tops generally align along said common joining plane; thereby interlocking said first and second bodies in a generally impermeable disposition. 